I was listening to my 1plus2 on the Tera earlier...as usual match made in heaven. I do agree that the 1plus2 benefits from a little volume crank up. Partly because of the limited isolation, but to me, mostly because of the soundstage and presentation. You have the musicians in front, quite a little far out. So you are always tempted to crank it up.
I have also just purchased Meier Quickstep amp as I find that Tera max output is sometimes not quite enough for me (for metal and guitar distortion in general it sometimes feels like it does not have quite enough kick for my taste) - although so far I have suspected that this may have more to do with RE-600 than Tera as I do not feel like more volume is ever needed when I pair Tera with Porta Pros).
Anyhow, Quickstep will be good to have around for sure and it will be interesting to see how stack of Tera->Quickstep->1plus2 does with artists like Hendrix, Neil Young with Crazy Horse, Zeppelin, etc. - I have very high hopes